Weft detecting mechanism for looms



May 30, 1961 c. R. KRONOFF I WEFT DETECTING MECHANISM FOR LOOMS Filed Feb. 6. 1959 INVENTOR CLARENCE R. KRONOFF ATTORNEY United States Patent WEFT DETECTING MECHANISM FOR LooMs Clarence R. Kronoff, Worcester, Mass., assignor to Crompton & Knowles Corporation, Worcester, Mass., a corporation of Massachusetts Filed Feb. 6, 1959, Ser. No. 791,553

6 Claims. (Cl. 139-273) uses a weft detector finger which is periodically engaged I by a weft or thread carrying bobbin to indicate the presence or depletion of weft thereof, the bobbin being mounted in a shuttle on a forwardly and backwardly reciprocating lay. The finger, commonly known also as a feeler, is pivotally mounted on a slidable carrier movable from a normal stationary rear position to an abnormal forward position and back again to rear position. The finger has a feeler tip end which is engaged by a bobbin during the forward movement of the'lay, and when a bobbin carrying sufiicient weft engages the tip as the lay advances, the tip end will be imbedded in the weft threads to cause the finger and carrier to be moved forwardly by the lay and to hold the finger against side slipping angular movement to prevent initiation of a weft replenishing operation. However, if the bobbin is sufiiciently depleted of weft, the tip when engaged by the bobbin will slide along the latter as the lay moves forwardly, and the finger will move angularly about its pivot without moving the carrier whereby initiation of a weft replenishing operation will be effected.

During the first part of a weft replenishing operation, the carrier will be in its rear position and the feeler tip will be within the shuttle and must be withdrawn topermit a fully wound bobbin to replace the depleted one. As is usual, means are provided to act on the carrier to move it forwardly from its rear position to withdraw the feeler 1 1 tip end from the shuttle incidentto a weft replenishing operation. This withdrawal, however, is rather rapid, and when the carrier reaches the end of its forward mo tion and starts to return to its normal rear position, the finger, due to its latent inertia, is capable of swinging angularly clockwise, Fig. 1, about its pivot to cause a false initiation of a weft replenishing operation as against a true or permissible initiation 'which only occurs when the finger has a side slipping motion and while the car'- rier is stationary in its normal rear position. It is therefore an important object of the invention to prevent a false initiation by providing simple means forming part of the finger to resist and overcome this latent inertia incident, during and subsequent to a weft replenishing operation.

It is another object of the invention to provide control means on the finger to act on the latter in such a manner as to overcome the tendency of the finger to move angularly clockwise and to prevent the latter from initiating a weft-replenishing operation when the carrier is moved 1 component parts of the detector finger,

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2 forwardly during a weft replenishing operation previously initiated.

Another object of the invention is to provide the finger with weight means to form a unit therebetween and to locate the weight means on the side of the axis of the finger pivot opposite to the side that the feeler tip is located such that the weight means is substantially directly opposite and in alignment with the feeler tip with respect to the axis.

Still another object of the invention is to provide sim ple means consisting of a weight which in itself is effective to maintain the finger dynamically balanced to prevent angular movement of the latter when the carrier is moved forwardly and rearwardly incident and subsequent to a weft replenishing operation respectively. a

A further object of the invention is to provide the finger with a weighted body element which has sufficient mass to counteract the above-mentioned latent inertia by applying a resistive force in a direction opposite to that in which said finger tends to move relative to the carrier due to the sliding movement of the latter between its rear and forward positions during a weft replenishing operation.

A still further object of the invention is to make a detector finger having a turning moment on one side of the finger pivot equal to the turning moment of the finger on the opposite side of the pivot whereby the equality of the turning moments prevents the finger from having an angular side slipping motion when'the carrier moves forwardly from its rear position and back again during a weft replenishing operation. Y T

In order that the invention may be clearly understood reference is made to the accompanying drawings which illustrate by way of example the embodiments of the invention and in which: i i V Fig. 1 is a plan view of a weft detecting mechanism having the invention applied thereto, certain of the parts being broken away and certain of the parts being in section, i T

Fig. 2 is a fragmentary end elevation looking inthe direction of arrow 2, Fig. 1,

Fig. 3 is an exploded perspective view showing the Fig. 4 is a perspective view of a weft detector finger made according to the present invention, and

Fig. 5 is a diagrammatic view showing the invention'as used with one type of means capable of initiating 'a weft replenishing operation whenever the detector finger 'has a side slipping motion.

Referring particularly to Figs. 1 and 2, a weft detecting mechanism, generally indicated by M, is mounted on a stationary base plate 2 held' fast to a bracket 3 which is fixed to a stationary part of the loom, not shown. The weft detecting mechanism M includes a slidable carrier 4 mounted on the base plate 2 for forward and rear ward movement with respect to the base plate an'da lug 5 on the carrier against which a compression spring '6 exerts a force to maintain the carrier 4 in normal rear position as indicated in Fig. 1.. The base .2 a fixed lug 7 thereon similar to lug 5, the springbeing interposed between the lugs and in contact therewith. An adjustable set screw 8 on the carrier 7 engages a Step9 on the base 2 to limit rearward motion of the carrier.- An arm 11 extends rearwardly from the carrier and mounts a stationary stud 12 to provide a pivotal support for a weft detector finger, generally indicated by D. A light coiled return spring 13 surrounds the pivot 12'and has one end thereof fastened to a collar 14 and the other end fixed to the detector finger. Collar 14 is held fast to stud or pivot 12 by a screw '15 and is capable of being angularly adjusted about stud 1210 tension or loosen z-the 3 spring. .A projection 16 extends laterally from the carrier fora purpose to be described hereinafter.

The detector finger D has a flat part 17 extending diagonally Iearwardly :from pivot 12 and terminating in a feeler tip end 18 around which a coil spring 19 is wrapped for engagement with a bobbin B, see .Fig. '1. The finger D is provided witha flatsupport arm 21 forwardof pivot 12 which .in effect is an extension of part 17. Arm 21 is so formed as to .be substantially in alignment with end 18 with respect to the axis of pivot 12. Adjustably fastened on the detector D is a cam member 22 having an arcuate surface 23 for engagement with a roll 24 .on an arm 25 pivotally mounted on a switch 26. The switch 26 is bolted as by screws 27 to a'plate 28 held fast to the carrier 4 by screws 29. Switch 26 has a pair of spaced contacts 31, see Fig. 5, which are connected by a blade 32 whenever part 17 moves to the right as viewed in Fig. 1 to complete an electrical circuit to cause energization of a solenoid 33 for a purpose described hereinafter.

Referring to Fig. 5, the usualreciprocating lay L has a shuttle box 34 mounted thereon to receive and eject therefrom shuttles during loom operation, one of the shuttles being indicated by the numeral 35. The usual bobbin transferring arm 36 operates in a well known manner during a weft replenishing operation to replace a depleted bobbin in the shuttle 35 with a fully wound one from a bobbin reserve magazine not'shown but well understood in the tart. Transferring arm 36 has a depending arm 37 which carries a roll 38 for engagement with the aforementioned projection 16 during a bobbin changing operation. The electric circuit referred to above includes a transformer 40 having one side connected to power lines 41 and 42 and the other side connected to wires 43 and 44. Wire 43 leads to the usual shipper switch S8 from which another wire 45 extends to the previously mentioned solenoid 33 having an elongated core 46 for coaction with the usual chopper lever 47. Wire 44 extends to switch 26 and is connected to one of the contacts 31. The other contact 31 is attached to a wire 48 which is also connected to the solenoid 33.

Except as set forth hereinafter, the matter thus far described with reference to the weft detecting mechanism M is of usual and well-known construction and operates in a manner well understood in the art. Switch 25 and cam 22 form no part of the present invention insofar as their structure and function are concerned and operate as set forth in copending application Serial No. 673,006 filed July 19, 1957 and for a further understanding of switch 25 and its operation relative to the cam 22, reference is made to the above cited application. It is to be understood that the present invention is not limited in its use to electromechanical types of detecting mechanisms as disclosed herein, but isalso adaptable for use wherever it is desired to prevent angular side slipping of a weft detector finger at improper times during :loom operation.

In carrying the present invention into effect, weft detector finger D is formed with an upstanding weighted body element 50, see Figs. l-4, which may be considered as control means for the finger. This element or weight is attached to support arm 21 in any approved manner as by brazing, welding, set screws, etc. Weight 50 is ,fastened to arm 21 so as to be substantially diametrically opposite tip end 18 with respect to the axis of hole 51, and when the finger as made in the present instance is assembled to pivot 12, weight 50 will also be substantially diametrically opposite end 18 with respect to the axis of pivot 12. As can be readily seen in Fig. l, the weight and its support arm are so arranged that the center of gravity of the arm and weight will be in a vertical plane passing through said finger and its tip andthe axis of pivot 12. By locating weight 50 as indicated in Fig. 1 on the side of pivot 12 opposite to that side in which tip 18 is located and maintaining weight 50, the axis of pivot 12 and the tip end 18 in alignment with-each other, the turning moment of part 17, due to its latent inertia above mentioned,

is equalled with respect to the turning moment of arm 21 and weight 50 to dynamically balance finger D to prevent angular side slipping of the latter when carrier 4 is moved forwardly incident and subsequent to a weft replenishing operation. Weight 50 has sufficient mass which is capable of applying a resistive force in the opposite direction to that in which the finger tends to rotate as set forth above and yet permits side slipping of the finger when'the latter engages a depleted bobbin. The weight of itself is capable of maintaining the finger in balance and stationary with respect to the carrier at all times during loom operation except when acted upon by a bobbin. In making the weft detector D, part 17 and arm 21 are manufactured in the usual shape as .in the past, see Fig. 3, whereafter weight 50 is simply fixed to arm 21 as above explained to form a weft detector finger unit as seen in Fig. 4.

In operation, the lay, while advancing, will present the bobbin B to feeler tip end ,18 for a weft indicating motion. If the bobbin has suflicient weft thereon, the coils of wire 19 on end 18 will be imbedded in the threads (not shown) on the bobbin and as the lay advances the finger D and the carrier 6 will also be advanced due to the fact that the feeler finger is prevented from slipping angularly, it being held stationary with respect to the carrier 4 by the impingement of the coils on the Weft. 'Ihis prevention signifies a sufiiciency of weft and requires no replenishment thereof. However, if the bobbin B is depleted of weft the feeler tip end '18 will have a side slipping angular motion to the'right, Fig. l, with respect to the carrier while the latter remains stationary. .As the finger side slips, cam 22 will actuate lever 25 to close switch 26 whereupon solenoid 33 will be energized to move core 46 underneath the usual chopper lever 47 which reciprocates vertically during loom operation as is usual. The coaction between core 46 and lever 47 is well known in the art, and itis deemed unnecessary here to further explain their operation except to state thatwhen lever 47 is interrupted by core .46 the magazine will be set for a weft replenishing operation.

During the first part of the weft replenishing operation, i.e., when the fully Wound bobbin starts to move to replace the depleted bobbin, the ,tip end 18 will be within shuttle 35 and must be withdrawn in order to permit a fully wound bobbin to replace a depleted one without causing damage either to the bobbins or the feeler tip. As the weft replenishing operation continues, arm 36, as is usual, will be moving a bobbin from the magazine downwardly towards the shuttle, and during this motion depending arm 37 will move roll 38 toengage projection 16 to .move the latter and the carrier 4 rather rapidly in a forward direction to withdraw the feeler tip end 18 from the shuttle. Because of the rapid forward motion of the carrier, finger D has a tendency, due to its latent inertia, to move angularly clockwise when the carrier reaches its abnormal forward position to initiate a weft replenishing operation at a time when it is not needed. When the earrieris in its forward position, replenishment will be completed and transferrer arm 36 will have a quick return to its original position, whereupon spring 6, which had been previously compressed by the forward motion ofthe carrier, will expand to exert a force on lug 5 to cause a rapid return of carrier 4-to its normal rear position. During this withdrawal and return of the carrier, the weight 50 acts to maintain finger ,D dynamically balanced so that cam 22 cannot move to initiate a false weft replenishing operation incident andsubsequent thereto.

From the foregoing it will be apparent that simple means have been provided in'the form of a weightedbody element forming part of the weft detector finger D to prevent ,side slipping of the .latter with respect to the carrier 4 whenever the latter is moved forwardly by roll 38 or rearwardlyby spring 6. Also, it will be seen that the weight 50 is so located on the finger with respect to theaxis of pivot 12and tip end 18 thatthe weightacts to apply a resistive force to the finger to overcome the tendency of the latter to move and to maintain the finger dynamically balanced as the carrier is moved incident, during and subsequent to a weft replenishing operation, the weight however, permitting angular motion of the finger with respect to the carrier when the bobbin is depleted of weft. Thus, it is by the simple expedient of adding a weight to the finger that false indication is prevented when the carrier moves abruptly or rapidly either forwardly or rearwardly. Moreover, the weight can easily be applied to existing weft detecting mechanisms in the field without requiring the manufacture of a new or different finger than is presently being used of the type set forth herein.

Having now particularly described and ascertained the nature of the invention and in what manner the same is to be performed, what is claimed is:

1. In a loom weft detecting mechanism having a rearwardly and forwardly slidable carrier movable in the latter direction during a weft replenishing operation and on which a pivot mounts a side slipping weft detector finger movable angularly with respect to said carrier to initiate a weft replenishing operation when the carrier is slid forwardly during said operation, the finger being provided with a feeler tip rearward of said pivot, a support arm forming part of said finger and diametrically opposite said tip, and a weight on said support arm substantially diametrically opposite said tip to prevent side slipping of said finger and said initiation when said carrier is moved forwardly during a weft replenishing operation, the center of gravity of said arm and weight being in a vertical plane passing through and along the length of said finger and its tip and said pivot.

2. The mechanism set forth in claim 1 wherein said weight and said finger form a unit such that the weight is always on that side of the axis of said pivot opposite to the side of said axis in which the feeler tip end of said finger is located, said weight being substantially directly opposite and in alignment with said feeler tip with respect to said axis.

3. In a loom weft detecting mechanism having a forwardly and rearwardly slidable carrier movable respectively incident and subsequent to a weft replenishing operation, said carrier having thereon a pivot and means to initiate a weft replenishing operation and a side slipping weft detector finger having a feeler tip and mounted for angular movement on said pivot for coaction with said initiating means, a support arm forming part of said finger and diametrically opposite said tip and a weight forming part of said finger to maintain the latter dynamically in balance during said forward and rearward motion of the carrier to prevent said angular movement and said initiation, said weight being so located on said finger such that the weight of itself is effective to prevent an angular side slipping motion of said finger when said carrier is moved forwardly and rearwardly incident and subsequent to a weft replenishing operation respectively.

4. In a loom weft detecting mechanism having a slidable carrier movable from a normal rear position to an abnormal forward position and back again incident and subsequent to a weft replenishing operation respectively, a side slipping weft detector finger pivotally mounted on said carrier for angular movement with respect to said carrier and having latent inertia tending to move said finger angularly during movement of said carrier between said positions to initiate a weft replenishing operation, and an element having a resistive mass and on said finger in a position to counteract said inertia to prevent said angular movement and said initiation.

5. The mechanism set forth in claim 4 wherein said element is a weighted body capable of applying a resistive force in a direction opposite to that in which said finger tends to move due to movement of said carrier between said positions, said force preventing angular movement of said finger with respect to said carrier.

6. The mechanism set forth in claim 4 wherein part of said finger is on one side of said pivot and has a turning moment in a direction which tends to move said part angularly to initiate said operation when the carrier moves between said positions and another part thereof is on the opposite side of said pivot to that of said first part and has a turning moment opposite to said direction to resist and overcome said tendency to prevent angular movement of said finger and said initiation when the carrier moves between said positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,664,008 Wakefield Mar. 27, 1928 1,826,637 Schmanska Oct. 6, 1931 2,050,066 Payne Aug. 4, 1936 2,506,258 Whitin May 2, 1950 

